Endoscopes are well-known in the art and are commonly used for numerous medical procedures. One such procedure is removing polyps, lesions or other types of targeted tissue from the gastrointestinal mucosal wall of a human subject.
Several drawbacks exist with conventional polypectomy removal techniques. Various cauterization devices have been developed to remove polyps. However, these devices sometimes cause serious thermal injury to the gastrointestinal wall, fail to remove the entire targeted tissue, or do not completely cauterize blood vessels which lead to excessive bleeding. Snare devices designed to encircle and remove polyps may not capture all the targeted tissue. Further, a physician may experience difficulty in securing the targeted tissue with the snare. Snaring only the minimal tissue required from the three layer wall, i.e., mucosa, submucosa, and muscularis, is also important. More specifically, to prevent complications, the muscularis tissue should be avoided in this type of procedure. In an effort to solve these and other problems, one technique used is sub-mucosal lift polypectomy which involves injecting the tissue with, for example a saline solution, to lift the tissue to a more favorable position. This technique improves complete transection. The injected fluid separation also insulates the outer muscle from cautery or thermal injury.
Various other procedures require a needle and a snare, including use of a needle to wash the site, applying dies for the purpose of highlighting diseased or abnormal tissue, for injecting tattoo medium for post-transection surveillance purposes, and hemostatic injection therapy for post-polypectomy bleeding. In these and other procedures requiring a snare and a needle, a physician must use two separate auxiliary instruments, and one at a time feed them in and out of the instrument channel, which increases the overall procedure time. Therefore, a need exists in the art for a snare injection device that offers an improvement over prior art designs.
The present invention is a device that includes a snare and a needle, each separately routed in one channel of a dual channel lumen. The needle may perform several functions during the procedure, including pre-procedure and post-procedure injections, and lifting the tissue during the procedure. The present invention also allows for immediate repeat injections which may be required due to absorption of the lift fluid by the gastrointestinal wall, without removal of the snare.
The present invention offers numerous other improvements over prior art needle devices including a needle limit mechanism, consistent 1:1 handle/needle axial movement in a variety of endoscope configurations, and puncture prevention features. In certain prior art designs, a needle could injure a patient by puncturing the sidewall of a device or deploying beyond a desired length to cause harm to a patient. As such, the present invention offers improvements in patient safety and ease of use for the physician.